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Technologies for the stabilization of elemental mercury

Technologies for the stabilization of elemental mercury. Sven Hagemann GRS. What is stabilization / solidification ? . Reduces the mobility of contaminants in the media by physically binding them within stabilized mass mass or inducing chemical reactions (US EPA 2007) 

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Technologies for the stabilization of elemental mercury

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  1. Technologies for the stabilization of elemental mercury Sven HagemannGRS

  2. Whatisstabilization/ solidification? • Reduces the mobility of contaminants in the media by physically binding them within stabilized mass mass or inducing chemical reactions (US EPA 2007)  • Solidification: liquid  solid by using additives lid) without changing the chemical properties of the wastes

  3. Typesofstabilizationtechnolgies • Chemical stabilization: Chemical transformation into more stable, less mobile chemical compound • Microencapsulation: Embedment of particles in impermeable matrix (e.g. cement) • Macroencapsulation: Coverage of waste material with impermeable material, e.g. polyethylene

  4. What is Stabilization of Mercury? • Conversion of liquid, elemental mercury into a much less hazardous solid, e.g. mercury sulphide • Why stabilization? • Solid, no risk of liquid spillage • Mercury vapour pressure below occupational safety limits • Mercury concentration in leachates below acceptance thresholds for disposal • Lower commercial value (reduced risk of theft) • Benefits: • Easier and safer to manage, transport, store and dispose

  5. Stabilization and Disposal Options for Mercury Wastes Extraction Hgfreewaste + Specially engineered landfill Waste containing mercury(e.g. end of life products) ? Stabilized elemental mercury Stabilized mercury waste Waste contaminated with mercury(e.g. soil, debris) Permanent storage in underground mines

  6. Technologies forthestabilizationofelementalmercury • Stabilization as mercury sulphide (HgS) or mercury selenide • Stabilization as mercury sulphide in a sulphur / (polymer) / (cement) matrix • Stabilization as amalgam

  7. Stabilization as mercury sulphide (HgS) or mercury selenide (HgSe) • Identicalprocesswithselenium, but muchmore expensive Heat + • Hg + S HgS • Mercury + Sulfur Mercury sulphide

  8. Stabilization as mercury sulphide in a sulphur / (polymer) / (cement) matrix • Twosteps: • Reactionofmercurywithsulphur • Mixing ofmercurysulphidewith liquid sulfur (and additives) Heat + PolymerCement Polyethylene Sand Heat + +

  9. Amalgam • Reactionofmercurywithanotherpowderedmetal (copper, zink) + • Hg + Cu (Hg,Cu) • Mercury + Copper Copper amalgam (an alloy)

  10. Update on Stabilization Technologies • Two new technologies developed by companies in Spain and Germany • Different approaches, similarily stable products • Products fulfil US and EU leaching criteria • One in pilot stadium, another brought to full scale: licensed and commercially used • Similar processes are under development by other companies

  11. New Stabilization Technologies -1 Process developed by German company (2009-2010) • Mixing of Hg + sulphur under vacuum at 250-350 °C • Gas phase reaction: pure solid mercury sulphide (cinnabar) • Full-scale plant in operation: up to 800 kg per batch/ up to 1000 t per year per plant • Plant constructible as ‘mobile version’ bring plant to waste Similarprocessesunderdevelopmentbycompanys in the USA and France

  12. New Stabilization Technologies -1 • Process developed by German company (2009-2010) • 200 t Hg already stabilized and disposed (May 2011) • Cost: 2,000 EUR/ t ~2,800 USD/t (including final disposal) Similarprocessunderdevelopmentby a US company

  13. New Stabilization Technologies - 2 • US company (2008-2010) • Addition of Hg to sulphur under vacuum (450-590°C) • Product: red mercury sulphide • Pilot: 50 kg per batch/ 275 kg per day, scale-up to 200kg/ batch or higher envisaged • Product: pure red mercury sulphide • Reported cost: 11,000 – 13,000 EUR/ t

  14. New Stabilization Technologies - 3 • Process developed by Spanish company (2009) • 1) Stabilization as mercury sulphide by milling mercury with sulphur, then • 2) encapsulation in liquid sulphur/ gravel/ sand/ polymer (< 150°C) • Product: dark brown concrete like material of high physical and chemical durability • Could be moulded in any form • 2 kg per batch (pilot apparatus), larger plant under development (2.5 t/ day)

  15. New Stabilization Technologies - 3 • Process developed by Spanish company (2009) • Estimated costs: 3,500 – 4,500 EUR for full scale plant • Similarprocessesdevelopedby • 2 US companies (Mixing ofelementalmercury, sulphur polymer andsulphides), oneusedtostabilize10 t radioactivemercury • Korean University (sulpurcement/ polyethylenematrix)

  16. Stabilization Technologies: Amalgamation • Many companies • Mixing of elemental mercury with metal powder (e.g. zink or copper) • Well known physical process at room temperature, no chemical reaction • Product: soft metallic solid • Recommended process for solidification of radioactive mercury • mercury vapour pressure may be as high as of elemental mercury (at least for zinc amalgam) not regarded as adequate of non-radioactive mercury

  17. Stabilization Technologies: Conclusion • Stabilization technologies (at least one) available at full-scale • Costs start at 2,800 USD/t • Product could be transported and stored in drums or big bags:  avoid long-term storage of elemental mercury • Allows new concept: disposal after stabilization

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